US regulators have made inquiries to Robinhood about the trading restrictions the app put on stocks such as GameStop during the Reddit-led rallies earlier this year.

Robinhood temporarily stopped users from buying dozens of stocks that day traders who use the WallStreetBets subreddit had targeted in a short squeeze assault.

In a regulatory filing, the firm says it has received "inquiries" about its actions from the SEC, Finra, a number of state attorneys general offices and several state securities regulators.

Meanwhile, Robinhood says it is aware of around 46 putative class actions and three individual actions that have been filed against it.

"The complaints generally allege breach of contract, breach of the implied covenant of good faith and fair dealing, negligence, breach of fiduciary duty and other common law claims," says the filing, adding: "We believe that the claims in these lawsuits are without merit and intend to defend against them vigorously."